Backpacks are widely used and accepted for carrying loads from student's books to military equipment and supplies. Backpacks have evolved over the years from a simple bag with a strap to more sophisticated systems for better weight distribution. Since children and students commonly use backpacks for carrying books and school supplies, the American Chiropractic Association has set forth certain guidelines and recommendations as the improper use and wearing backpacks can lead to muscle imbalance that can result in chronic back and neck problems. As a general recommendation, the backpack and load should weigh no more than 5 to 10 percent of the wearer's body weight and the backpack should have shoulder straps that are adjustable so the backpack can be fitted to the wearer's body. In an attempt to improve both the comfort and the convenience of backpacks, various pack designs can be found in the prior art patent literature.
For example U.S. Pat. No. 5,465,886 discloses a pack which includes a bag and a belt attached to the bag. The belt has a first flexible belt portion extending from the bag at one side of the torso and terminating at a free end. A second flexible belt portion extends from the bag at the other side of the torso terminating at a free end. A connecting device on each belt portion connects the belt portions. The connecting device on the first belt portion is movable longitudinally. When the connecting devices are engaged, the free end of the first belt is adapted to be inserted through the loop and pulled against the loop to cinch the belt tightly around the wearer's torso.
U.S. Pat. No. 5,228,609 discloses an improved fanny-pack which includes a back-support section to which a carry bag is attached, including a semi-rigid plate of polyethylene. Attached to the back-support section are a pair of waistband members. Additional straps attached at the bottom and top of the carry bag pass through loop members anchored outboard of the belt and may be pulled and secured to the carry bag.
A backpack carrier assembly is shown in U.S. Pat. No. 4,982,884. In this patent, a pivotal coupling is provided with the back portion at or above the center of gravity of the backpack so the backpack is free to swing from side to side behind the hips of the wearer. Low friction blocks, pads, rollers or surfaces are provided in order to reduce frictional forces.
U.S. Pat. No. 4,878,606 discloses a harness for a shoulder-supported bag. The harness restrains movement of the bag while in use and inhibits posture deformation of the wearer. The harness partially redistributes the load. A pelvic belt enhances the stability by retaining the bag in a substantially constant position. A shoulder pad and strap are restrained by an underarm strap to reduce stress.
U.S. Pat. No. 5,806,741 discloses a load-carrying system comprising a pack frame and waist-encircling belt. The belt includes a receptacle attached to the exterior side of the belt located midway between its ends. The receptacle has an opening to receive the male formation. The load-carrying system further includes at least one interfering member attached to the receptacle and positioned within the receptacle opening. The interfering member is adapted for engaging the engagement portion of the male formation. The interfering member prevents the male formation from becoming dislodged from the receptacle when the pack frame is in a generally vertical orientation and allows the male formation to become to dislodged when orientation of the pack frame is less than vertical.
U.S. Pat. No. 5,361,955 discloses a modular backpack for carrying heavy loads. The backpack includes a back panel with a polyfoam layer, a stretch fabric cover and a fabric layer between the polyfoam layer and the back panel, all molded to define a number of smaller polyfoam pads. The carry bag is attached to the back panel in a separate waist support having separate mobile left and right waistbands is fastened thereto. A pair of generally triangular stress panels are stitched to the lower part of the back panel on each side so as to overlay the outside of the waistband pads and the pads of the shoulder straps.
Thus, from the foregoing, it will be seen that there are numerous designs for backpacks and fanny-packs which attempt to stabilize the load, increase comfort and increase the convenience to the wearer. However, one significant disadvantage to backpacks of the type described above is that it is generally necessary for the backpack to be entirely removed from the back of the wearer before the backpack wearer can access the contents of the backpack. The wearer must disengage the backpack, then open the pack to access the contents and thereafter replace the backpack in a position on the wearer's back. This procedure requires considerable time and is inconvenient, particularly if the wearer is engaged in a strenuous activity such as hiking, rock climbing, rescue operations, running or adventure racing.
Accordingly, it is highly desirable to have a backpack which, when worn, can be shifted from a normal position on the back of the wearer to a position in which the wearer can gain access to the contents without the necessity of having to remove the backpack.
My prior patent, U.S. Pat. No. 5,437,403 discloses an improved travel pack or backpack which can be readily accessed by the wearer when the pack is positioned at the front of the wearer which can be moved or shifted between the front and back of the wearer without requiring the pack to be removed and then donned again when the backpack is in the use position. The pack may be worn and shifted beneath an outer coat or garment and may also be shifted even when the wearer is in a prone position. However, while it is believed that the system of this patent provides substantial functional benefits in permitting shifting of the pack, there nevertheless exists a need for further improvements which enhance the versatility, ease of use and convenience of a dynamic pack system which can be shifted without the wearer having to interrupt his or her activity to access or shift the pack.